I think it is highly irrelevant how complex fixing the breakage is, it will probably almost always be trivial, but that's not the point: Think e.g. about a package which didn't really need any update for a few years, its maintainer is inactive (nothing to recently, so that's OK), and which is a transitive dependency of a number of other packages. This will effectively mean lots of broken packages for weeks or even longer. Fixing breakage from the AMP or FTP proposals was trivial, too, but nevertheless a bit painful. 

To me the fundamental question which should be answered before any detail question is: Should we go on and continuously break minor things (i.e. basically give up any stability guarantees) or should we collect a bunch of changes first (leaving vital things untouched for that time) and release all those changes together, in longer intervals? That's IMHO a tough question which we somehow avoided to answer up to now. I would like to see a broader discussion like this first, both approaches have their pros and cons, and whatever we do, there should be some kind of consensus behind it.

Cheers,

   S.

P.S.: Just for the record: I'm leaning towards the "lots-of-changes-after-a-longer-time" approach, otherwise I see a flood of #ifdefs and tons of failing builds coming our way... :-P